The 27-year-old Keeping Up With the Kardashians costar is set to become a father for the second time later this summer, and his pregnant girlfriend, Kourtney Kardashian, wants him to start focusing more on his family -- instead of going out and partying.

Angry that her man was out until the wee hours of the morning hanging with her sister, Kim, Kourtney, 32, begs him to ditch his late-night lifestyle on Sunday's episode of the E! reality hit. "You wouldn't answer my texts, but you were sending me pictures of you guys," Kourtney fumes in a preview from the episode.

"I'm not into staying home by myself every night while you guys are partying it up. I wake up in the middle of the night seeing if [you're] home -- it's disrupting my sleep," Kourtney -- also the mom of Mason, 2 -- continues.

Kourtney then calls up Kim to let her know she needs to find a new party pal. "You can find your own boyfriend to hang out with because mine is going to be at home with his pregnant girlfriend and son," she snaps.